The present invention relates to heat sink fans for cooling heat generating devices, and more particularly pertains to heat sink fans for cooling semiconductor devices such as microprocessors.
A heat sink fan for cooling a heat generating device such as a semiconductor device is disclosed in, for example U.S. Pat. No. 5,484,013. As disclosed in U.S. Pat. No. 5,484,013, the conventional heat sink fan includes a heat sink that is to be mounted on a heat generating device and a housing that is to be detachably coupled to the heat sink. A fan attached to the housing forcibly cools the heat sink by air flow generated by the fan.
FIG. 10 illustrates an example of a conventional heat sink fan. In general, in order to facilitate engagement of a housing 302 with a heat sink 304 as well as to facilitate coupling of the housing 302 with the heat sink 304, a heat sink fan 300 for cooling a semiconductor device such as a microprocessor is configured such that the housing 302 can be attached to and detached from the heat sink 304 with the housing 302 being rotated relative to the heat sink 304 about an axis extending vertically. In addition, the housing 302 and the heat sink 304 are provided with first and second interlocking means 306a and 306b for detachably retaining the housing 302 and the heat sink 304 relatively at position. The first interlocking means 306a comprises, for example, a combination of a flange 307 and a pawl 308 that disengageably engages the flange 307 and that can move relative to the flange 307. For example, the flange 307 is provided on the housing 302, and the pawl 308 on the heat sink 304, respectively. Furthermore, the second interlocking means 306b comprises a combination of a projection 310 and a depression 312 which disengageably engage each other. For example, the projection 310 is provided on the housing 302, and the depression 312 on the heat sink 304, respectively.
In such a conventional heat sink fan 300, when the housing 302 is turned in a predetermined direction relative to the heat sink 304 with the flange 307 of the first interlocking means 306a engaging the pawl 308, the projection 310 of the second interlocking means 306b is brought into engagement with the depression 312 to detachably couple the housing 302 with the heat sink 304. When the housing 302 is turned in the opposite direction from the coupled position, relative to the heat sink 304, the projection 310 of the second interlocking means 306b disengages from the depression 312, followed by disengagement of the flange 307 of the first interlocking means 306a from the pawl 308, so that the housing 302 is separated from the heat sink 304.
However, as the engagement structure as mentioned above is constructed such that the housing and the heat sink are relatively rotated, it can be applied to a case where a heat generating device is square in shape, whereas it is not suited to a case, by for example, when such a heat generating device is rectangular, (the housing and the heat sink will also be rectangular correspondingly). Consequently, it is desired to have an engagement structure that is applicable irrespective of the geometry or shape of a heat generating device.
Further, U.S. Pat. No. 5,484,013 discloses a heat sink fan in which the housing and the heat sink are to be coupled with each other with the housing being moved to the heat sink in the direction perpendicular to the plate of the heat sink. However, this heat sink fan has a complex structure for disengageably engaging the heat sink with the housing.
Still furthermore, U.S. Pat. No. 5,615,998 discloses a heat sink fan having a coupling structure that disengageably engages each other without rotating the housing relative to the heat sink. In this type of heat sink fan, however, the geometry and detaching structure of the heat sink and the housing are also complicate. Such a complicate structure will be a factor of increasing costs of molds and correspondingly raising production costs.